Process of making succinic acid



June 5, 1923.

J F. NORRIS ET AL PROCESS OF MAKING SUCCINIC ACID Filed Oct. 20, 1*?2 W g m county of Middlesex and State of latented June 5, 1923.

UNITED STATES 1,451,191 PATENT OFFICE.

JAMES F. NORRIS AND EDMUND 0. CUMMINGS, OF CAMBRIDGE, MASSACHUSETTS.

success or naxmo scccnnc son).

Application filed October 20, 1922. Serial No. 595,754.

To all whom it may concern:

Be it known that we, J AMES F. Nonms and EDMUND O. CUMMINcs, citizens of the United States, residing at Cambrid in the ,assachusetts, have invented certain new and useful Improvements in Processes of Making Succimc Acid, of which the following is a specification.

This invention relates to a process of makin succinic acidfrom fumaric and maleic acids, and has more 5 ific reference to an electrolytic process 0 reducing the latter acids to succmic acid.

It is an object of this invention to provide a method for effecting a high conversion of fumaric and maleic acids into succinic acid by electrolytic reductiom In carrying out this process a cell is used,

owever,.other electrodes which are not attached may be used, for example, iron,copper, graphite, carbon, tin, zinc and mercury. The electrolyte consists of a dilute mineral acid, such as sulphuric or hydrochloric acid, which will not dissolve the anode and cathode under the'conditions existing duri or both the maric and maleic acids in solution or partly dissolved and partly suspended therein. The fumaric and maleic acids are not completely soluble in the electrolyte under the preferred conditions of carrying out the process.

Reference is to be had to the accom anymg drawing which shows, in more or ess diagrammatic form, the preferred form of a paratus for carrying out the reduction. T e apparatus comprises a vessel (1) of material capable of reslsting the action of the electrolytes, such as glass, the anode (2) and the cathode (3), which ma be perforated. The electrodes are preferab' made of sheet lead. The ap aratus shows t e use of the porous cup (4 preferably of unglazed porcelain, which acts as a die. hragm, and surrounds the cathode (3) an is positioned upon the late (5) at the bottom of the vessel (1 This diaphragm may, however, under certain conditions be dispensed wish. The leads (6) and (7) are connected to the electrodes, and the apparatus is rovided with the voltmeter 8) ammeter (9 and adjustable resistance 10) whereb the current passing through t 0 cell may be determined and re lated The apparatus may also provided with em lo ing referabl alead anode and lead cathode if the electrolysis, having either .1

the stirrer (11) operated by the shaft (12), pulley (113) and belt (14).

The e ectrol te consisting of the dispersion of either the umaric or maleic acid, or both of these acids in the dilute mineral acid is placed in this cell and electrolyzed, preferaly stirring the electrolyte until the desired dispersion is obtained. However, stirring may be dispensed with, without appreciably afl'ecting the current density.

The reduction should be carried out under conditions where gassing and loss of hydrogen is prevented as much as possible. A high current density cannot be used if the concentration'in the solution of the dissolved fumaric or maleic acids is low, because under such conditions fiilSSll'lg and loss of hydrogen will result. At 'gher tem eratures, the solubilities of the fumaric and increased and therefore greater current densities maly be employed under such conditions without osing hydrogen by gassing and as a result the time required for the reduction is greatly reduced when operating at higher temperatures and with higher current densities, thus resulting in increased current efficiency.

In selecting the current density to be used, as great an amount of current is passed maleic acids are.

through the apertures as can be employed 1 without gassing. As the reduction proceeds, the concentration of the fumaric or maleic acid decreases, thus promoting evolution of hydrogen and when gassing begins the current dens1t is decreased.

The pre erred operating temperatures are from 60 or 70 to or 0., and the amount of acid em loyed is such that the dispersions of the .umaric or maleic acids therein are not too thick. Although lead anodes and lead cathodes are preferred in carrying out this process, it is to be understood that this invention is not so limited but other substance such as graphite, may be substituted for t e lead.

The following is a specific example of reducing fumaric acid, without employing a diaphragm. About 60 o fumaric acid are added to about 900 c. c. of water at 80 C, and placed inthe cell, and to this is slowly added a solution of 15 c. c. H SO, (specific gravity 1.84 in 100 c. c. ofwater.

ny fumaric acid w ich is precipitated by the H,SO, is ke t in suspension by means of the stirrer. he electrolysis is then begun, using a cathodic current density of 6.5

electrolfytically reducing a a H amperes per square decimeter until about 88% of the theoretical current has been passed. The current density may then be reduced to about 2.5 amperes per square decimeter until about 10% excess current has been used.

After the reduction, the solution is transferred to a suitable evaporator and then concentrated, and the succinic acid crystallizes from the concentrated liquor upon cooling. By this process yields of 90% or over may be obtained.

The porous diaphragm has been found of greater value when electrolytically reducing maleic acid than fumaric acid, and the electrolytic reduction of the latter may be carried on very efiiciently without the use of the diaphragm.

The following example illustrates a process of preparing succinic acid from maleic acid, usin a diaphragm, Within the porous cup there is placed about 120 grams of maleic acid in a solution of about 15 c, c. H SO (specific gravity 1.84) in about 400 c. c. of water; In the anode compartment a 5% sulphuric acid solution is used. The reduction is then proceeded with as in the previous example, using a cathodic current density of about 8 amperes per square decimeter until about 96% of the theoretical current has passed, and then a current density of about 3 amperes per square decimeter until about 5% excess of the theoretical current has passed. After reduction, the cathodic solution is transferred to a suitable evaporator and then concentrated and the succinic acid recovered by crystallization from the concentrated liquor.

The present invention is not limited to the specific details set forth in the foregoing examples which should be construed as illustrative and not by way of limitation, and

in view of the numerous modifications whichmay be efi'ected therein without departing from the spirit and scope of this invention, it is desired that only such limitations be imposed as are indicated in the appended claims.

We claim as our invention:

1. In a process of making succinic acid, electrolytically reducing a dispersion of an acid of the formula (},,H (COOH) in a solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis.

2. In a process of makin succinic acid, ispersion of an acid 0 the formula ,(COOH), in a dilute solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis.

3. In a process of making succinic acid, electrolytically reducing a dispersion of said acid in a dilute solution oi sulphuricacid.

111 a process of making succinic acid,

reducing by means of a current of high density a is ersion of an acid of the formula G,H OOH) in a solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis and decreasing the current density as the concentration of the dissolved organic acid is lowered.

5.In a process of making succinic acid, reducing by means of a current of hi h densityla dispersion of an acid of the ormula C (COOI'I) in a dilute solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis and decreasing the current density as the concentration of the dissolved organic acid is lowered.

6. In a process of making succinic acid, reducing by means of a current of hi h density a dispersion of an acid of the ormula C,H,(COOH) in a dilute solution of sulphuric acid and decreasing the current density as the concentration of the dissolved or nic acid is lowered.

In a process of makin succinic acid, electrolytically reducing, wit a. porous diaphragm, a dis ersion of an acid of the for mula 0 H, C OH), in a solution of a mineral acid w ich will not react in substantial amounts with the electrodes employed for the electrolysis.

8. In a process of makin electrolytically reducing, with a porous diaphragm, a dis ersion of an acid of the formula C H (C OH), in a dilute solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis.

9. In a process of making1 succinic acid, electrolytically reducing, wit a porous diaphragm, a dispersion of an acid of the formula C H (COOH) in a dilute solution of sulphuric acid.

10. In a process of making succinic acid, electrolytically reducing at temperatures of -90 (1., a dis ersion of an acid of the formula C,H,(CO H) in a solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis.

'11. In a process of making succinic acid electrolytically reducing, at temperatures 0 TO-90 C., a dispersion of an acid of the formula C H (COOH) in a dilute solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis.

12. In a process of making succinic acid electrolytically reducing, at temperatures 0% 7090 C. and with a porous diaphragm, a disfiersion of an acid of the formula C (COOH) in a solution of a mineral acid which will not react in substantial amounts with the electrodes employed for rie electrolysis.

succinic acid,

mula C,H,(C

13. In a process of makin succinic acid, electrolytically reducin w ile stirring, a dis ersion of an aci of the formula C ,(COOH), in a solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis.

14. In a process of makin succinic acid, electrolytically reducing, whi e stirring and with a porous diaphraglnli, a dis ersion of an acid of the formula C (CO H), in a solution of a mineral acid which will not react in substantial amounts with the electrodes emplo ed for the electrolysis.

15. n a process of makin succinic acid, electrolytically reducing, while stirring and with a porous diaphraaili, a dispersion of an acid of the formula C (COOH) in a solution of a mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis, and then effecting crystallization of the succinic acid from the resulting liquid.

16. In a process of makin electrolytically reducin with phragm, a dis ersion o OH) in a dilute solution of succinic acid, a porous diafrom t e resultin an acid of the fora mineral acid which will not react in substantial amounts with the electrodes employed for the electrolysis, and then efiectmg crystallization of t e succinic acid from the resulting liquid.

17. In a process of making succinic acid, electrolytically reducing, at temperatures of 70-90 C., while stirring and with a porous diaphragm; a dis ersion of an acid of the formula C,H,(C OH) in a dilute solution of a mineral acid which will not react in substantial, amounts with the electrodes employed for the electrolysis, and then effectmg crystallization of the succinic acid from the resulting liquid.

18. In-a process of makin succinic acid from fumaric and maleic acids, electrolytically reducing at 7090 C., while stirring and with a porous diaphrgm, a dispersion of an acid of the formula H,(COOH) in a dilute solution of sulphuric acid, and then efiectin crystallizatlion of the succinic acid iqui In testimony w ereof we aliix our signatures.

JAMES F. NORRIS. EDMUND O. CUMMINGS.

Certificate of 06mm.

It is hereby certified that in Letters Patent No. 1,457,791, granted June 5, 1923, upon the application of James F. Norris and Edmund O. Cummings, of Cambridge, Massachusetts for an improvement in Processes of Making Succinic Acid, errors appear in the minted s ification requiring correction as follows: Page 1, line 22, for the word attaches? read attacked, and line 86, for the word apertures read apparatus; page 2, lines 63 and 64, claim 3, strike out the words said acid and insert instead an acid of the fomula 0,H,(000H),.; page 3, line 44, claim 18, strike out the words from fumaric and maleic acids and that the said Letters Patent should be read with these corrections therein that the same mag conform to the record of the ease in the Patent Oflioe.

igned and sealed this 26th day of June, A. D., 1923.

[m] KARL FENNING,

Acting Commissioner of Pam. 

